Analysis of Holy Sonnet XIII: What If This Present Were The World's Last Night?

What if this present were the world's last night?
Mark in my heart, O soul, where thou dost dwell,
The picture of Christ crucified, and tell
Whether that countenance can thee affright,
Tears in his eyes quench the amazing light,
Blood fills his frowns, which from his pierced head fell.
And can that tongue adjudge thee unto hell,
Which prayed forgiveness for his foes' fierce spite?
No, no; but as in my idolatry
I said to all my profane mistresses,
Beauty, of pity, foulness only is
A sign of rigour: so I say to thee,
To wicked spirits are horrid shapes assigned,
This beauteous form assures a piteous mind.